ELABORATION OF THE GLYCERINE SOAP BASE 

 Theoretical notions 

 Without being able to delve much into the subject, I will try to explain the principle of transparency. Under normal conditions the soap usually crystallizes in an amorphous way, that is, disorderly. It is the arrangement of this type of crystals that provides opacity to soap. There are other forms of crystallization that give a transparent result and those are what interest us.

There are ingredients that favor this type of crystallization. Mainly alcohols. Because of its price, alcohol was no longer used to the benefit of glycerin that was cheaper for soap makers of the time. That's where the name glycerin soap comes from. You also have to consider the loading ingredients. It  is called load to those elements that serve to give greater performance  to the oil and this means that with the same amount of oil comes more  soap. Some fillers, such as starch, talc, clay, etc., also produce opacity,  but some, such as sugar or heavy soda (hydrated sodium carbonate), not  only do not produce opacity, but promote transparency.

Keeping this in mind, it will be easier to understand what the ingredients of the formula that said to be part of are used.

The realization of this soap requires a little more experience on the part of whoever does it. For this reason, it is advisable to have started earlier in the production of cold soap and in the hot process. Furthermore, the use of solvents (such as alcohol) entails additional dangers. It is not recommended to make this soap by minors and of course I am not responsible for the misuse of this information. In any
always give a review of the basic safety rules.

Preparation of the glycerin soap base The starting recipe is as follows (we are going to elaborate 1 kg):

- Coconut oil ...... 20% (200gr)
- Castor oil ...... 10% (100gr)
Stearic acid ...... 10% (100gr)
-So caustic ... 5% (50gr)
-diluted in Water ............... 10% (100gr)
-Sugar ............ 20% (200gr)
-diluted in Water ............ 10% (100gr)
-Alcohol 96º ......... 15% (150gr)

Coconut  soap provides the foam, castor soap improves transparency and stearic  acid provides hardness (in this case it is essential for consistency). Sugar provides transparency and consistency and alcohol transparency. The process is hot, mixing the previously melted oils, with the previously mixed lye. Due to the characteristics of stearic acid, saponification is immediate. The mass solidifies a lot at once but do not despair and stir until it is homogeneous and semiliquid. The pot should be high enough to prevent the possible rise of the  dough that may come to boil because of the speed of the stearic  saponification process.

Once  everything is well homogenous it is put in the oven (between 80 and  90ºC) for 2 hours to get the total saponification of the fats. This will be verified by the pH test, either with phenolphthalein, with strips or with the tongue. When  the saponification is completed, the syrup previously made with sugar  and water will be added at a temperature of 60ºC until it is completely  homogenized, which gives the soap a more plastic appearance and  consistency. Finally, it must be added (avoiding vapors and any flame) little by little alcohol. This causes the dough to become completely transparent and very, very liquid. Almost like water, nobody worry. I sometimes use the blender at very slow speed to complete the mix.

The  result is to strain it for the possible remains of undissolved soap and  pour it into a mold if possible that can be covered by letting it rest  until it is completely cooled. Our glycerin base must already be made. It  may happen that there is an upper layer of foam that has no major  relevance when removing it and some of the unsaponified oil may also be  in that upper layer. That's why it's so important to do the pH test. In this case, the excess of soda must be compensated when the base is re-founded. The variations offered by the recipe are endless, of course. But  we must highlight the existence of Propylene Glycol and Dipropylene  Glycol as solvents to replace part of alcohol or glycerin and sorbitol  which also produces more transparency. Also the salt in very moderate amount produces more hardness which allows the use of other oils.